If only talking about Part 1 DB and offering some fair level of subjective favouritism, about top 50 material. Despite its fluctuating arc quality, it was for the most part a well executed action/adventure story with likeable characters and a well paced change in tone. Including the "Z" portion of the manga, I'd be inclined to let favouritism place it at the same spot due to some of the influential ideas, a few interesting characters such as Saiyan Arc Piccolo and it overall being a logical next step up until the end of the Freeza Arc. Viewing it more objectively, however, the drop in consistent continuity and characters in the Cell and Boo Arcs would have me placing it outside of the top 60, though I give it a pass for at least not going quite as downhill as most other Shonen do in their final arcs (Part 2 OP, Naruto, Bleach, YYH, Part 2 HnK, etc.).
If forced to include Super into the mix, it's hard to say how low it'd go with how much of a disservice it is. Thankfully, you can view the original manga and DB/Z anime without needing to see GT or Super tarnishing their overall quality, so I don't tend to include them when talking about the series' overall quality.